I replaced existing bumper since it was not exactly straight. This item was good quality, well packed and easily mounted. Keep in mind it does NOT include hardware.
Very satisfied. Had to drill holes for all of the rubber impact mouldings. Now issues or imperfections. Pics of installation can be seen here: http://www.7173mustangs.com/thread-new-rear-bumper-drilling-new-rubber-installation
not nearly as thick as orig. but looks good also corners are not the same as factory.